1. Field of the Invention
The present invention relates generally to log singulators, and more particularly, is concerned with a log singulator having a 360-degree rotatable lifting arm.
2. Description of the Prior Art
Log singulators have been described in the prior art. However, none of the prior art devices disclose the unique features of the present invention.
In U.S. Pat. No. 5,423,417, dated Jun. 13, 1995, Redekop disclosed a log singulator for sorting, feeding and indexing in a downstream direction a stack of logs into a stream of logs which has a first notched step and a first set of collectively actuable lift arms pivotable about a first axis, and a second set of collectively actuable lift arms downstream of the first set of lift arms, actuable independently of the first set of collectively actuable lift arms and pivotable about a second axis, the first set of lift arms actuable from a lowered position to a raised position whereby the first set of lift arms are engageable with a log at a first engagement point thereby to raise the log from the stack of logs, the first axis downstream of the first engagement point relative to the direction of movement of said logs in said stream of logs, the first axis generally below the first notched step, the first notched step adapted to receive and hold the stack of logs, the first set of lift arms in the raised position positioning the log so as to deposit the log into a second notched step below the first set of lift arms in the raised position and downstream of the first notched step, the second set of lift arms actuable from a lowered position to a raised position whereby the second set of lift arms are engageable with the log in the second notched step at a second engagement point thereby to raise the log from the second notched step, the second axis downstream of the second engagement point and generally below the second notched step, the second set of lift arms in the raised position positioning the log so as to deposit the log from the log singulator.
In U.S. Pat. No. 5,174,351, dated Dec. 29, 1992, Lindenblatt, et al., disclosed an ending apparatus for positioning elongate objects comprising, in combination, object singulating equipment for separating a plurality of elongate objects in an inlet area into single objects while moving the objects in a first direction to an outlet area, and object support rollers intermediate the inlet and outlet area for supporting a separated, single elongate object. The object support rollers are adapted to move the elongate object in a second direction toward a reference surface independently of the object""s movement in the first direction on the singulating device. The reference surface stops movement of the elongate object to establish a predetermined position for the elongate object. Establishing the position of the object permits more efficient handling during further processing.
In U.S. Pat. No. 4,585,114, dated Apr. 29, 1986, Liliano disclosed an apparatus for the transfer of mandrels from a lube conveyer to a parallel mandrel pre-insertion line which comprises a plurality of transfer devices each of which has an arm for the direct transfer of the mandrels which is disappearingly movable transversely between the said conveyor and the said line, and a further pair of arms, one fixed and one movable, having upper saw-tooth profiles cooperating to effect a stepwise displacement of the mandrels between the conveyor and the said line.
While these log singulators may be suitable for the purposes for which they were designed, they would not be as suitable for the purposes of the present invention, as hereinafter described.
The present invention discloses a device for singulating individual logs from groups of logs for linear or transverse processing. The present invention discloses a log singulator having a fully rotatable lifter arm member, i.e., 360 degrees rotatable, which is used to singulate logs from groups of logs. The rotatable axle of the lifter arm may be located above the upstream xe2x80x9cVxe2x80x9d of the log cradle member. Furthermore, the lifter arm of the present invention will positively push the logs over the top point of the log cradle because it is rounded at the top point, thereby allowing the tip of lifter arm to remain in contact with the log. Lifter arms with 1 to 4 lifter arm tips are disclosed.
In log utilization facilities, the need exists to singulate individual logs from groups of logs for linear or transverse processing. Several types of devices have been developed to accomplish this task. The devices currently available utilize a method of lifting logs over fixed generally V-shaped log cradles via a reciprocating motion generated by mechanical components. This particular motion has several disadvantages: the return motion of the lifting mechanism utilizes time in which the forward flow of logs being singulated is stopped; the reciprocating motion requires a bulky, complicated mechanism to perform the forward and backward motion; as logs are lifted over the top of the V-shaped log cradle, movement of the log to complete the motion to the bottom of the upstream V-shaped pocket is dependent on gravity; logs with knots or that are crooked may not slide into proper position; the reciprocating lifting device is of an eccentric design, meaning that its weight is not balanced, and, this off center weight disadvantage utilizes approximately 25% of the total power to move a log from stage to stage; the V-shaped log cradles surfaces may be covered with smooth steel plating, and, the plating makes crooked or knotty logs xe2x80x9cstand offxe2x80x9d from the bottom of the V log cradle, and, if the logs are too far away from the lift position of the pocket, they will not be transferred from stage to stage.
Objects and advantages of the present invention are to disclose a singulation device which does not reciprocate, but makes a full 360-degree motion. The rotary motion device of the present invention has several advantages. Since the rotary singulation motion is continuous, in a constant direction, there is no lost time waiting or the lifting device to return to start position and, therefore, productivity of the rotary device is greatly improved over the reciprocating device. The drive unit for the rotary motion is direct connected to the lift mechanism, eliminating the need for a complicated mechanical means, e.g., a transmission, to develop the reciprocating motion. Because the motion is continuous, the shape of the rotating lift arm is designed so that the log is positively guided into the bottom of the upstream V-shaped log cradle which eliminates the possibility of knots or crooked logs hanging on the pocket surfaces. The rotary lifting device is of a concentric design, meaning that its weight is substantially totally balanced. Due to it being balanced, a power savings of up to 25% per stage can be realized to lift the same size log as a reciprocating design. In the rotary design, an open skid concept is utilized, meaning that the V-shaped log cradles are not covered with steel plating. However, alternatively, the skids may be plated over. The open design allows crooked or knotty logs to lay in the open V-shaped log cradle, conforming to the shape of the log. This permits the log to be lifted into the proper position so that logs can be more efficiently transferred from stage to stage of the log singulator.
The foregoing and other objects and advantages will appear from the description to follow. In the description reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. In the accompanying drawings, like reference characters designate the same or similar parts throughout the several views.